The present invention relates generally to keyboards, which may be used with any machines for communicating, storing, processing or retrieving information, such as computers, typewriters, telegraphs, type composing machines, siphering machines, etc.
When the typewriter became a commercial success in the 1890's after a long history of experiment, a variety of keyboard layouts were in use. Some machines used the type-bar mechanisms which later became universal for wholly mechanical typewriters. Because the early type-bar mechanisms were liable to jam if adjacent keys were struck in quick succession, the letters were arranged on the keyboard to avoid such sequences. The resulting so-called "Universal" keyboard, now generally known as QWERTY from its letter sequence, is inefficient in human terms, as only 50% of letters struck lie on the most used row, and the fingers must make many reaches to the other rows. A common standard keyboard layout, developed with the objective to exclude the type-bar jams, proved a commercial necessity and has become the standard for all languages written with the Latin alphabet.
With the advent of electronic computers the QWERTY keyboard has been enlarged by the addition of a ten key numerical keypad as used on calculators, duplicating the ten numeric keys on the top row of the typewriter layout to increase the speed of numeric data entry, at least four cursor movement keys, and a growing number of other machine function keys having fixed or program assigned meanings. Leading computer manufacturers are now supply universal word and data processing keyboards having over 100 keys.
Many investors have endeavored to improve the typewriter keyboard layout. The best known work is that of Dvorak et al, who described in 1932 a letter arrangement optimized in terms of carefully chosen criteria including letter frequencies and the relative strength and agility of the fingers. Other inventors have worked on the shape of the keyboard, variously proposing key rows curved to match the natural arc of the fingers, multiple key rows disposed in double curved bowl shapes to ease the reaches, thumb keys oriented nearly at right angles to the fingers keys to better exploit the strength and agility of the thumbs, and a general outward tilt of the two sides of the keyboard for the comfort of wrists. The gain in speed from any of these performance optimized keyboards appears limited, and is tentatively estimated in Siebel (1972) at no more than 10%.
The speed of 40-60 words per minute expected from a competent typist requires so-called `touch-typing`, that is reading manuscript while simultaneously operating the keyboard with only tectile and audible feedback. To do this, the stimulus-response bonds which link letters and common group of letters to the finger movements, which type them, must be thoroughly learnt. These bonds are sequence dependent, and the reaches over the rows and columns make them complex. Untrained persons such as the journalists, authors, professionals and managers who now increasingly use computers without the intervention of specialists keyboard operators are unable to key at more than about 15 words per minute, even with much practical experience, because in typing the hands must "hang" over the keyboard to allow the finger out-stretching in the plane and direction which does not coincide with the natural least constrained contraction-extension movement of fingers. As professionals and managers are generally not willing to undergo formal keyboard training, the computer is of less benefit to them than it could be.
The cursor movement keys of the extended QWERTY keyboard give very limited movement capability. A single press moves the cursor one place up, down or sideways, as a king moves in chess. A press and hold brings into action after a delay of about half a second an auto-repeat function which moves the cursor at a fixed, rather slow speed in the chosen direction, but still moving it as a rook. Moves between two arbitrary points have to be made as a series of zig-zags. The cursor cannot move as a queen. The fixed auto-repeat speed, necessarily a comprise, is time-consuming on long course moves and yet fast enough to lead to overshoots if the user is not very careful. To overcome these limitations, auxiliary devices such as the mouse, used to generate XY coordinates, is being adopted for cursor movement and for graphical work. The ease of cursor movement with these devices is particularly important in supporting machine languages which exploit to the full the human preference for communicating by showing rather than telling. These auxiliary devices have however the disadvantage in textual work that one hand must be moved frequently between the keyboard and the mouse, which is disorienting and time-consuming.
A further disadvantage of the conventional keyboard is the high risk of accidentally initiating computer action by pressing the `Enter` key before one means to, due to its placement at the front of the keyboard next to the right shift key. The occasional proposals in the data processing art for thumb keys, operating in a plane differing from that of the other finger keys, are related to the unused strength and agility of thumbs which belong to the strongest fingers which are least active over the keyboard.